I communicated with several Tencent employees, using e-mail addresses I found via Google search, as there were no useful/working links or e-mail addresses to be found on (the English language version of) Tencent Weibo itself.

Again they recommended the "Lost password" process even though I told them several times and in several ways that I had not lost my password.

Eventually they gave me back access to my account without having to go through the standard (and deeply flawed) account recovery process.

After that, I was also finally able to set up security questions for my account, which has been a big problem throughout this, because answering these questions is crucial to getting back access to a Tencent account, even though the whole idea of security questions was not in the English version of setting up a Tencent account when I created my account.

Cartoon from XKCD about security questions.

Based on my latest experience, it seems that Tencent have translated a few more pages to English since I first created my account and since I first lost access to it.

But there are still a lot of things missing from the English version of Tencent Weibo (like a help page!). And I have still never received a useful explanation about why I was denied access to my account. But I will give Tencent Weibo another try.